Lauryl Betaine Research Articles

Simulation Studies on the Role of Lauryl Betaine in Modulating the Stability of AOS Surfactant-Stabilized Foams Used in Enhanced Oil Recovery

The stability of foam in the presence of oil is of fundamental interest in enhanced oil recovery processes using foam for mobility control. Experimentally, it is known that lauryl betaine (LB) increases foam stability of certain anionic surfactants, and LB is referred to as a foam booster. However, the molecular basis for this effect is not well understood. Using molecular dynamics simulations, here we study a system of LB and alpha olefin sulfonate (AOS-14), an anionic surfactant that is used as a foam stabilizer. We monitor the area per molecule, a quantity that correlates with the surface shear viscosity, and the surface dilatational modulus to infer the stability of the various mixtures. We find that the influence of LB is nonmonotonic: the area per molecule and surface dilatational modulus have a minimum and maximum, respectively, around 30% LB in the monolayer. We show that this net effect has its basis in two competing effects: the favorable interaction between LB and AOS-14 that tends to shrink th...

Carbon Dot-Based Platform for Simultaneous Bacterial Distinguishment and Antibacterial Applications.

In this work, we prepared quaternized carbon dots (CDs) with simultaneous antibacterial and bacterial differentiation capabilities using a simple carboxyl-amine reaction between lauryl betaine and amine-functionalized CDs. The obtained quaternized CDs have several fascinating properties/abilities: (1) A long fluorescence emission wavelength ensures the exceptional bacterial imaging capability, including the super-resolution imaging ability; (2) the polarity-sensitive fluorescence emission property leads to significantly enhanced fluorescence when the quaternized CDs interact with bacteria; (3) the presence of both hydrophobic hydrocarbon chains and positively charged quaternary ammonium groups makes the CDs selectively attach to Gram-positive bacteria, realizing the bacterial differentiation; (4) excellent antimicrobial activity is seen against Gram-positive bacteria with a minimum inhibitory concentration of 8 μg/mL for Staphylococcus aureus. Besides, the quaternized CDs are highly stable in various aqueous solutions and exhibit negligible cytotoxicity, suggesting that they hold great promise for clinical applications. Compared to the traditional Gram staining method, the selective Gram-positive bacterial imaging achieved by the quaternized CDs provides a much simpler and faster method for bacterial differentiation. In summary, by combining selective Gram-positive bacterial recognition, super-resolution imaging, and exceptional antibacterial activity into a single system, the quaternized CDs represent a novel kind of metal-free nanoparticle-based antibiotics for antibacterial application and a new type of reagent for efficient bacterial differentiation.

Wettability Alteration and Foam Mobility Control in a Layered, 2D Heterogeneous Sandpack

Summary In a layered, 2D heterogeneous sandpack with a 19:1 permeability contrast that was preferentially oil-wet, the recovery by waterflood was only 49.1% of original oil in place (OOIP) because of injected water flowing through the high-permeability zone, leaving the low-permeability zone unswept. To enhance oil recovery, an anionic surfactant blend (NI) was injected that altered the wettability and lowered the interfacial tension (IFT). Once IFT was reduced to ultralow values, the adverse effect of capillarity retaining oil was eliminated. Gravity-driven vertical countercurrent flow then exchanged fluids between high- and low-permeability zones during a 42-day system shut-in. Cumulative recovery after a subsequent foam flood was 94.6% OOIP, even though foam strength was weak. Recovery with chemical flood (incremental recovered oil/waterflood remaining oil) was 89.4%. An alternative method is to apply foam mobility control as a robust viscous-force-dominant process with no initial surfactant injection and shut-in. The light crude oil studied in this paper was extremely detrimental to foam generation. However, the addition of lauryl betaine to NI (NIB) at a weight ratio of 1:2 (NI:lauryl betaine) made the new blend a good foaming agent with and without the presence of the crude oil. NIB by itself as an IFT-reducing and foaming agent is shown to be effective in various secondary and tertiary alkaline/surfactant/foam (ASF) processes in water-wet 1D homogeneous sandpacks and in an oil-wet heterogeneous layered system with a 34:1 permeability ratio.

Luminescence of LaF3:Ln3+ Nanocrystal Dispersions in Ionic Liquids

Ionic liquids were used as solvents for dispersing luminescent lanthanide-doped LaF3:Ln3+ nanocrystals (Ln3+ = Eu3+ and Nd3+). To increase the solubility of the inorganic nanoparticles in the ionic liquids, the nanocrystals were prepared with different stabilizing ligands, i.e., citrate, N,N,N-trimethylglycine (betaine), and lauryldimethylglycine (lauryl betaine). LaF3:5%Ln3+:betaine could successfully be dispersed in 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [C4mpyr][Tf2N], 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate [C4mpyr][TfO], and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C4mim][Tf2N] but only in limited amounts. Red photoluminescence was observed for the europium(III)-containing nanoparticles and near-infrared luminescence for the neodymium(III)-containing systems.

A simple and sensitive assay of nucleic acids based on the enhanced resonance light scattering of zwitterionics

A new assay of nucleic acids at nanogram level was established based on the enhanced resonance light scattering (RLS) signals of two zwitterionics cocamidopropyl hydroxysultaine (HSB) and lauryl betaine (BS-12). Under optimum conditions, the weak RLS signal of HSB is enhanced by nucleic acids, and the enhanced RLS intensity is proportional to the concentration of nucleic acids in the range of 0.02–7.3 mg l −1 for calf thymus DNA and 0.01–8.6 mg l −1 for fish sperm DNA. The detection limits were 1.5 ng ml −1 for calf thymus DNA and 1.9 ng ml −1 for fish sperm DNA. Plasmid DNA extracted from K-12-HB101 colt was determined with satisfactory results.